Refactor REGISTER_VPCI_INIT to contain more capability specific
information, this will benefit further follow-on changes to hide
capability when initialization fails.

What's more, change the definition of init_header() since it is
not a capability and it is needed for all devices' PCI config space.

After refactor, the "priority" of initializing capabilities isn't
needed anymore, so delete its related codes.

Note:
Call vpci_make_msix_hole() in the end of init_msix() since the change
of sequence of init_header() and init_msix().

The cleanup hook is also added in this change, even if it's still
unused. Further changes will make use of it.

Signed-off-by: Jiqian Chen <Jiqian.Chen@amd.com>
---
cc: "Roger Pau Monné" <roger.pau@citrix.com>
cc: Andrew Cooper <andrew.cooper3@citrix.com>
cc: Anthony PERARD <anthony.perard@vates.tech>
cc: Michal Orzel <michal.orzel@amd.com>
cc: Jan Beulich <jbeulich@suse.com>
cc: Julien Grall <julien@xen.org>
cc: Stefano Stabellini <sstabellini@kernel.org>
---
v7->v8 changes:
* Recover vpci_make_msix_hole() call in modify_decoding(), which was  deleted by wrong.
* Add some comment to describe why need to add vpci_make_msix_hole() in init_msix().

v6->v7 changes:
* Change the pointer parameter of cleanup hook of vpci_capability_t to be const.
  If change parameter of init hook to be const will affect init_msix, and it assigns pdev
  to struct vpci_msix, so keep no const to expanding the impact.
* Delete the vpci_make_msix_hole() call in modify_decoding().
* Change __start_vpci_array from vpci_capability_t* array to vpci_capability_t array.
* Change the name "finit##_t" to be "name##_entry" and add a "name" parameter to macro
  REGISTER_VPCI_CAPABILITY.

v5->v6 changes:
* Rename REGISTER_PCI_CAPABILITY to REGISTER_VPCI_CAPABILITY.
* Move vpci_capability_t entry from ".data.vpci" to ".data.rel.ro.vpci" and
  move the instances of VPCI_ARRAY in the linker scripts before *(.data.rel.ro).
* Change _start/end_vpci_array[] to be const pointer array.

v4->v5 changes:
* Rename REGISTER_VPCI_CAP to REGISTER_PCI_CAPABILITY, rename REGISTER_VPCI_LEGACY_CAP to
  REGISTER_VPCI_CAP, rename REGISTER_VPCI_EXTENDED_CAP to REGISTER_VPCI_EXTCAP.
* Change cleanup hook of vpci_capability_t from void to int.

v3->v4 changes
* Delete the useless trailing dot of section ".data.vpci".
* Add description about priority since this patch removes the initializing priority of
  capabilities and priority is not needed anymore.
* Change the hook name from fini to cleanup.
* Change the name x and y to be finit and fclean.
* Remove the unnecessary check "!capability->init"

v2->v3 changes:
* This is separated from patch "vpci: Hide capability when it fails to initialize" of v2.
* Delete __maybe_unused attribute of "out" in function vpci_assign_devic().
* Rename REGISTER_VPCI_EXTEND_CAP to REGISTER_VPCI_EXTENDED_CAP.

v1->v2 changes:
* Removed the "priorities" of initializing capabilities since it isn't used anymore.
* Added new function vpci_capability_mask() and vpci_ext_capability_mask() to remove
  failed capability from list.
* Called vpci_make_msix_hole() in the end of init_msix().

Best regards,
Jiqian Chen.
---
 xen/arch/arm/xen.lds.S    |  3 +--
 xen/arch/ppc/xen.lds.S    |  3 +--
 xen/arch/riscv/xen.lds.S  |  3 +--
 xen/arch/x86/xen.lds.S    |  2 +-
 xen/drivers/vpci/header.c |  3 +--
 xen/drivers/vpci/msi.c    |  2 +-
 xen/drivers/vpci/msix.c   | 13 ++++++++++--
 xen/drivers/vpci/rebar.c  |  2 +-
 xen/drivers/vpci/vpci.c   | 44 ++++++++++++++++++++++++++++++---------
 xen/include/xen/vpci.h    | 29 +++++++++++++++++++-------
 xen/include/xen/xen.lds.h |  2 +-
 11 files changed, 74 insertions(+), 32 deletions(-)

diff --git a/xen/arch/arm/xen.lds.S b/xen/arch/arm/xen.lds.S
index 5bfbe1e92c1e..9f30c3a13ed1 100644
--- a/xen/arch/arm/xen.lds.S
+++ b/xen/arch/arm/xen.lds.S
@@ -57,6 +57,7 @@ SECTIONS
 
        *(.rodata)
        *(.rodata.*)
+       VPCI_ARRAY
        *(.data.rel.ro)
        *(.data.rel.ro.*)
 
@@ -64,8 +65,6 @@ SECTIONS
        __proc_info_start = .;
        *(.proc.info)
        __proc_info_end = .;
-
-       VPCI_ARRAY
   } :text
 
 #if defined(BUILD_ID)
diff --git a/xen/arch/ppc/xen.lds.S b/xen/arch/ppc/xen.lds.S
index 1366e2819eed..1de0b77fc6b9 100644
--- a/xen/arch/ppc/xen.lds.S
+++ b/xen/arch/ppc/xen.lds.S
@@ -51,11 +51,10 @@ SECTIONS
 
         *(.rodata)
         *(.rodata.*)
+        VPCI_ARRAY
         *(.data.rel.ro)
         *(.data.rel.ro.*)
 
-        VPCI_ARRAY
-
         . = ALIGN(POINTER_ALIGN);
     } :text
 
diff --git a/xen/arch/riscv/xen.lds.S b/xen/arch/riscv/xen.lds.S
index 8c3c06de01f6..edcadff90bfe 100644
--- a/xen/arch/riscv/xen.lds.S
+++ b/xen/arch/riscv/xen.lds.S
@@ -46,11 +46,10 @@ SECTIONS
 
         *(.rodata)
         *(.rodata.*)
+        VPCI_ARRAY
         *(.data.rel.ro)
         *(.data.rel.ro.*)
 
-        VPCI_ARRAY
-
         . = ALIGN(POINTER_ALIGN);
     } :text
 
diff --git a/xen/arch/x86/xen.lds.S b/xen/arch/x86/xen.lds.S
index 636c7768aa3c..8e9cac75b09e 100644
--- a/xen/arch/x86/xen.lds.S
+++ b/xen/arch/x86/xen.lds.S
@@ -135,6 +135,7 @@ SECTIONS
 
        *(.rodata)
        *(.rodata.*)
+       VPCI_ARRAY
        *(.data.rel.ro)
        *(.data.rel.ro.*)
 
@@ -148,7 +149,6 @@ SECTIONS
        *(.note.gnu.build-id)
        __note_gnu_build_id_end = .;
 #endif
-       VPCI_ARRAY
   } PHDR(text)
 
 #if defined(CONFIG_PVH_GUEST) && !defined(EFI)
diff --git a/xen/drivers/vpci/header.c b/xen/drivers/vpci/header.c
index f537f3f25d2a..469f4977441a 100644
--- a/xen/drivers/vpci/header.c
+++ b/xen/drivers/vpci/header.c
@@ -858,7 +858,7 @@ static int vpci_init_ext_capability_list(const struct pci_dev *pdev)
     return 0;
 }
 
-static int cf_check init_header(struct pci_dev *pdev)
+int vpci_init_header(struct pci_dev *pdev)
 {
     uint16_t cmd;
     uint64_t addr, size;
@@ -1054,7 +1054,6 @@ static int cf_check init_header(struct pci_dev *pdev)
     pci_conf_write16(pdev->sbdf, PCI_COMMAND, cmd);
     return rc;
 }
-REGISTER_VPCI_INIT(init_header, VPCI_PRIORITY_MIDDLE);
 
 /*
  * Local variables:
diff --git a/xen/drivers/vpci/msi.c b/xen/drivers/vpci/msi.c
index 66e5a8a116be..c3eba4e14870 100644
--- a/xen/drivers/vpci/msi.c
+++ b/xen/drivers/vpci/msi.c
@@ -270,7 +270,7 @@ static int cf_check init_msi(struct pci_dev *pdev)
 
     return 0;
 }
-REGISTER_VPCI_INIT(init_msi, VPCI_PRIORITY_LOW);
+REGISTER_VPCI_CAP(MSI, init_msi, NULL);
 
 void vpci_dump_msi(void)
 {
diff --git a/xen/drivers/vpci/msix.c b/xen/drivers/vpci/msix.c
index 74211301ba10..eb3e7dcd1068 100644
--- a/xen/drivers/vpci/msix.c
+++ b/xen/drivers/vpci/msix.c
@@ -703,9 +703,18 @@ static int cf_check init_msix(struct pci_dev *pdev)
     pdev->vpci->msix = msix;
     list_add(&msix->next, &d->arch.hvm.msix_tables);
 
-    return 0;
+    /*
+     * vPCI header initialization will have mapped the whole BAR into the
+     * p2m, as MSI-X capability was not yet initialized.  Crave a hole for
+     * the MSI-X table here, so that Xen can trap accesses.
+     */
+    spin_lock(&pdev->vpci->lock);
+    rc = vpci_make_msix_hole(pdev);
+    spin_unlock(&pdev->vpci->lock);
+
+    return rc;
 }
-REGISTER_VPCI_INIT(init_msix, VPCI_PRIORITY_HIGH);
+REGISTER_VPCI_CAP(MSIX, init_msix, NULL);
 
 /*
  * Local variables:
diff --git a/xen/drivers/vpci/rebar.c b/xen/drivers/vpci/rebar.c
index 793937449af7..3c18792d9bcd 100644
--- a/xen/drivers/vpci/rebar.c
+++ b/xen/drivers/vpci/rebar.c
@@ -118,7 +118,7 @@ static int cf_check init_rebar(struct pci_dev *pdev)
 
     return 0;
 }
-REGISTER_VPCI_INIT(init_rebar, VPCI_PRIORITY_LOW);
+REGISTER_VPCI_EXTCAP(REBAR, init_rebar, NULL);
 
 /*
  * Local variables:
diff --git a/xen/drivers/vpci/vpci.c b/xen/drivers/vpci/vpci.c
index 09988f04c27c..7778acee0df6 100644
--- a/xen/drivers/vpci/vpci.c
+++ b/xen/drivers/vpci/vpci.c
@@ -36,8 +36,8 @@ struct vpci_register {
 };
 
 #ifdef __XEN__
-extern vpci_register_init_t *const __start_vpci_array[];
-extern vpci_register_init_t *const __end_vpci_array[];
+extern const vpci_capability_t __start_vpci_array[];
+extern const vpci_capability_t __end_vpci_array[];
 #define NUM_VPCI_INIT (__end_vpci_array - __start_vpci_array)
 
 #ifdef CONFIG_HAS_VPCI_GUEST_SUPPORT
@@ -83,6 +83,32 @@ static int assign_virtual_sbdf(struct pci_dev *pdev)
 
 #endif /* CONFIG_HAS_VPCI_GUEST_SUPPORT */
 
+static int vpci_init_capabilities(struct pci_dev *pdev)
+{
+    for ( unsigned int i = 0; i < NUM_VPCI_INIT; i++ )
+    {
+        const vpci_capability_t *capability = &__start_vpci_array[i];
+        const unsigned int cap = capability->id;
+        const bool is_ext = capability->is_ext;
+        unsigned int pos = 0;
+        int rc;
+
+        if ( !is_ext )
+            pos = pci_find_cap_offset(pdev->sbdf, cap);
+        else if ( is_hardware_domain(pdev->domain) )
+            pos = pci_find_ext_capability(pdev->sbdf, cap);
+
+        if ( !pos )
+            continue;
+
+        rc = capability->init(pdev);
+        if ( rc )
+            return rc;
+    }
+
+    return 0;
+}
+
 void vpci_deassign_device(struct pci_dev *pdev)
 {
     unsigned int i;
@@ -128,7 +154,6 @@ void vpci_deassign_device(struct pci_dev *pdev)
 
 int vpci_assign_device(struct pci_dev *pdev)
 {
-    unsigned int i;
     const unsigned long *ro_map;
     int rc = 0;
 
@@ -159,14 +184,13 @@ int vpci_assign_device(struct pci_dev *pdev)
         goto out;
 #endif
 
-    for ( i = 0; i < NUM_VPCI_INIT; i++ )
-    {
-        rc = __start_vpci_array[i](pdev);
-        if ( rc )
-            break;
-    }
+    rc = vpci_init_header(pdev);
+    if ( rc )
+        goto out;
+
+    rc = vpci_init_capabilities(pdev);
 
- out: __maybe_unused;
+ out:
     if ( rc )
         vpci_deassign_device(pdev);
 
diff --git a/xen/include/xen/vpci.h b/xen/include/xen/vpci.h
index 6a481a4e89d3..17cfecb0aabf 100644
--- a/xen/include/xen/vpci.h
+++ b/xen/include/xen/vpci.h
@@ -13,11 +13,12 @@ typedef uint32_t vpci_read_t(const struct pci_dev *pdev, unsigned int reg,
 typedef void vpci_write_t(const struct pci_dev *pdev, unsigned int reg,
                           uint32_t val, void *data);
 
-typedef int vpci_register_init_t(struct pci_dev *dev);
-
-#define VPCI_PRIORITY_HIGH      "1"
-#define VPCI_PRIORITY_MIDDLE    "5"
-#define VPCI_PRIORITY_LOW       "9"
+typedef struct {
+    unsigned int id;
+    bool is_ext;
+    int (* init)(struct pci_dev *pdev);
+    int (* cleanup)(const struct pci_dev *pdev);
+} vpci_capability_t;
 
 #define VPCI_ECAM_BDF(addr)     (((addr) & 0x0ffff000) >> 12)
 
@@ -29,9 +30,21 @@ typedef int vpci_register_init_t(struct pci_dev *dev);
  */
 #define VPCI_MAX_VIRT_DEV       (PCI_SLOT(~0) + 1)
 
-#define REGISTER_VPCI_INIT(x, p)                \
-  static vpci_register_init_t *const x##_entry  \
-               __used_section(".data.vpci." p) = (x)
+#define REGISTER_VPCI_CAPABILITY(cap, name, finit, fclean, ext) \
+    static const vpci_capability_t name##_entry \
+        __used_section(".data.rel.ro.vpci") = { \
+        .id = (cap), \
+        .init = (finit), \
+        .cleanup = (fclean), \
+        .is_ext = (ext), \
+    }
+
+#define REGISTER_VPCI_CAP(name, finit, fclean) \
+    REGISTER_VPCI_CAPABILITY(PCI_CAP_ID_##name, name, finit, fclean, false)
+#define REGISTER_VPCI_EXTCAP(name, finit, fclean) \
+    REGISTER_VPCI_CAPABILITY(PCI_EXT_CAP_ID_##name, name, finit, fclean, true)
+
+int __must_check vpci_init_header(struct pci_dev *pdev);
 
 /* Assign vPCI to device by adding handlers. */
 int __must_check vpci_assign_device(struct pci_dev *pdev);
diff --git a/xen/include/xen/xen.lds.h b/xen/include/xen/xen.lds.h
index 793d0e11450c..b126dfe88792 100644
--- a/xen/include/xen/xen.lds.h
+++ b/xen/include/xen/xen.lds.h
@@ -188,7 +188,7 @@
 #define VPCI_ARRAY               \
        . = ALIGN(POINTER_ALIGN); \
        __start_vpci_array = .;   \
-       *(SORT(.data.vpci.*))     \
+       *(.data.rel.ro.vpci)      \
        __end_vpci_array = .;
 #else
 #define VPCI_ARRAY
-- 
2.34.1

On Thu, Jul 24, 2025 at 01:50:00PM +0800, Jiqian Chen wrote:
> Refactor REGISTER_VPCI_INIT to contain more capability specific
> information, this will benefit further follow-on changes to hide
> capability when initialization fails.
> 
> What's more, change the definition of init_header() since it is
> not a capability and it is needed for all devices' PCI config space.
> 
> After refactor, the "priority" of initializing capabilities isn't
> needed anymore, so delete its related codes.
> 
> Note:
> Call vpci_make_msix_hole() in the end of init_msix() since the change
> of sequence of init_header() and init_msix().
> 
> The cleanup hook is also added in this change, even if it's still
> unused. Further changes will make use of it.
> 
> Signed-off-by: Jiqian Chen <Jiqian.Chen@amd.com>
> ---
> cc: "Roger Pau Monné" <roger.pau@citrix.com>
> cc: Andrew Cooper <andrew.cooper3@citrix.com>
> cc: Anthony PERARD <anthony.perard@vates.tech>
> cc: Michal Orzel <michal.orzel@amd.com>
> cc: Jan Beulich <jbeulich@suse.com>
> cc: Julien Grall <julien@xen.org>
> cc: Stefano Stabellini <sstabellini@kernel.org>
> ---
> v7->v8 changes:
> * Recover vpci_make_msix_hole() call in modify_decoding(), which was  deleted by wrong.
> * Add some comment to describe why need to add vpci_make_msix_hole() in init_msix().
> 
> v6->v7 changes:
> * Change the pointer parameter of cleanup hook of vpci_capability_t to be const.
>   If change parameter of init hook to be const will affect init_msix, and it assigns pdev
>   to struct vpci_msix, so keep no const to expanding the impact.
> * Delete the vpci_make_msix_hole() call in modify_decoding().
> * Change __start_vpci_array from vpci_capability_t* array to vpci_capability_t array.
> * Change the name "finit##_t" to be "name##_entry" and add a "name" parameter to macro
>   REGISTER_VPCI_CAPABILITY.
> 
> v5->v6 changes:
> * Rename REGISTER_PCI_CAPABILITY to REGISTER_VPCI_CAPABILITY.
> * Move vpci_capability_t entry from ".data.vpci" to ".data.rel.ro.vpci" and
>   move the instances of VPCI_ARRAY in the linker scripts before *(.data.rel.ro).
> * Change _start/end_vpci_array[] to be const pointer array.
> 
> v4->v5 changes:
> * Rename REGISTER_VPCI_CAP to REGISTER_PCI_CAPABILITY, rename REGISTER_VPCI_LEGACY_CAP to
>   REGISTER_VPCI_CAP, rename REGISTER_VPCI_EXTENDED_CAP to REGISTER_VPCI_EXTCAP.
> * Change cleanup hook of vpci_capability_t from void to int.
> 
> v3->v4 changes
> * Delete the useless trailing dot of section ".data.vpci".
> * Add description about priority since this patch removes the initializing priority of
>   capabilities and priority is not needed anymore.
> * Change the hook name from fini to cleanup.
> * Change the name x and y to be finit and fclean.
> * Remove the unnecessary check "!capability->init"
> 
> v2->v3 changes:
> * This is separated from patch "vpci: Hide capability when it fails to initialize" of v2.
> * Delete __maybe_unused attribute of "out" in function vpci_assign_devic().
> * Rename REGISTER_VPCI_EXTEND_CAP to REGISTER_VPCI_EXTENDED_CAP.
> 
> v1->v2 changes:
> * Removed the "priorities" of initializing capabilities since it isn't used anymore.
> * Added new function vpci_capability_mask() and vpci_ext_capability_mask() to remove
>   failed capability from list.
> * Called vpci_make_msix_hole() in the end of init_msix().
> 
> Best regards,
> Jiqian Chen.
> ---
>  xen/arch/arm/xen.lds.S    |  3 +--
>  xen/arch/ppc/xen.lds.S    |  3 +--
>  xen/arch/riscv/xen.lds.S  |  3 +--
>  xen/arch/x86/xen.lds.S    |  2 +-
>  xen/drivers/vpci/header.c |  3 +--
>  xen/drivers/vpci/msi.c    |  2 +-
>  xen/drivers/vpci/msix.c   | 13 ++++++++++--
>  xen/drivers/vpci/rebar.c  |  2 +-
>  xen/drivers/vpci/vpci.c   | 44 ++++++++++++++++++++++++++++++---------
>  xen/include/xen/vpci.h    | 29 +++++++++++++++++++-------
>  xen/include/xen/xen.lds.h |  2 +-
>  11 files changed, 74 insertions(+), 32 deletions(-)
> 
> diff --git a/xen/arch/arm/xen.lds.S b/xen/arch/arm/xen.lds.S
> index 5bfbe1e92c1e..9f30c3a13ed1 100644
> --- a/xen/arch/arm/xen.lds.S
> +++ b/xen/arch/arm/xen.lds.S
> @@ -57,6 +57,7 @@ SECTIONS
>  
>         *(.rodata)
>         *(.rodata.*)
> +       VPCI_ARRAY
>         *(.data.rel.ro)
>         *(.data.rel.ro.*)
>  
> @@ -64,8 +65,6 @@ SECTIONS
>         __proc_info_start = .;
>         *(.proc.info)
>         __proc_info_end = .;
> -
> -       VPCI_ARRAY
>    } :text
>  
>  #if defined(BUILD_ID)
> diff --git a/xen/arch/ppc/xen.lds.S b/xen/arch/ppc/xen.lds.S
> index 1366e2819eed..1de0b77fc6b9 100644
> --- a/xen/arch/ppc/xen.lds.S
> +++ b/xen/arch/ppc/xen.lds.S
> @@ -51,11 +51,10 @@ SECTIONS
>  
>          *(.rodata)
>          *(.rodata.*)
> +        VPCI_ARRAY
>          *(.data.rel.ro)
>          *(.data.rel.ro.*)
>  
> -        VPCI_ARRAY
> -
>          . = ALIGN(POINTER_ALIGN);
>      } :text
>  
> diff --git a/xen/arch/riscv/xen.lds.S b/xen/arch/riscv/xen.lds.S
> index 8c3c06de01f6..edcadff90bfe 100644
> --- a/xen/arch/riscv/xen.lds.S
> +++ b/xen/arch/riscv/xen.lds.S
> @@ -46,11 +46,10 @@ SECTIONS
>  
>          *(.rodata)
>          *(.rodata.*)
> +        VPCI_ARRAY
>          *(.data.rel.ro)
>          *(.data.rel.ro.*)
>  
> -        VPCI_ARRAY
> -
>          . = ALIGN(POINTER_ALIGN);
>      } :text
>  
> diff --git a/xen/arch/x86/xen.lds.S b/xen/arch/x86/xen.lds.S
> index 636c7768aa3c..8e9cac75b09e 100644
> --- a/xen/arch/x86/xen.lds.S
> +++ b/xen/arch/x86/xen.lds.S
> @@ -135,6 +135,7 @@ SECTIONS
>  
>         *(.rodata)
>         *(.rodata.*)
> +       VPCI_ARRAY
>         *(.data.rel.ro)
>         *(.data.rel.ro.*)
>  
> @@ -148,7 +149,6 @@ SECTIONS
>         *(.note.gnu.build-id)
>         __note_gnu_build_id_end = .;
>  #endif
> -       VPCI_ARRAY
>    } PHDR(text)
>  
>  #if defined(CONFIG_PVH_GUEST) && !defined(EFI)
> diff --git a/xen/drivers/vpci/header.c b/xen/drivers/vpci/header.c
> index f537f3f25d2a..469f4977441a 100644
> --- a/xen/drivers/vpci/header.c
> +++ b/xen/drivers/vpci/header.c
> @@ -858,7 +858,7 @@ static int vpci_init_ext_capability_list(const struct pci_dev *pdev)
>      return 0;
>  }
>  
> -static int cf_check init_header(struct pci_dev *pdev)
> +int vpci_init_header(struct pci_dev *pdev)
>  {
>      uint16_t cmd;
>      uint64_t addr, size;
> @@ -1054,7 +1054,6 @@ static int cf_check init_header(struct pci_dev *pdev)
>      pci_conf_write16(pdev->sbdf, PCI_COMMAND, cmd);
>      return rc;
>  }
> -REGISTER_VPCI_INIT(init_header, VPCI_PRIORITY_MIDDLE);
>  
>  /*
>   * Local variables:
> diff --git a/xen/drivers/vpci/msi.c b/xen/drivers/vpci/msi.c
> index 66e5a8a116be..c3eba4e14870 100644
> --- a/xen/drivers/vpci/msi.c
> +++ b/xen/drivers/vpci/msi.c
> @@ -270,7 +270,7 @@ static int cf_check init_msi(struct pci_dev *pdev)
>  
>      return 0;
>  }
> -REGISTER_VPCI_INIT(init_msi, VPCI_PRIORITY_LOW);
> +REGISTER_VPCI_CAP(MSI, init_msi, NULL);
>  
>  void vpci_dump_msi(void)
>  {
> diff --git a/xen/drivers/vpci/msix.c b/xen/drivers/vpci/msix.c
> index 74211301ba10..eb3e7dcd1068 100644
> --- a/xen/drivers/vpci/msix.c
> +++ b/xen/drivers/vpci/msix.c
> @@ -703,9 +703,18 @@ static int cf_check init_msix(struct pci_dev *pdev)
>      pdev->vpci->msix = msix;
>      list_add(&msix->next, &d->arch.hvm.msix_tables);
>  
> -    return 0;
> +    /*
> +     * vPCI header initialization will have mapped the whole BAR into the
> +     * p2m, as MSI-X capability was not yet initialized.  Crave a hole for
> +     * the MSI-X table here, so that Xen can trap accesses.
> +     */
> +    spin_lock(&pdev->vpci->lock);
> +    rc = vpci_make_msix_hole(pdev);
> +    spin_unlock(&pdev->vpci->lock);

I should have asked in the last version, but why do you take the vPCI
lock here?

The path that ASSERTs the lock is held should never be taken when
called from init_msix().  Is there some path I'm missing in
vpci_make_msix_hole() that requires the vCPI lock to be held?

The rest LGTM.

Thanks, Roger.

On 2025/7/24 22:28, Roger Pau Monné wrote:
> On Thu, Jul 24, 2025 at 01:50:00PM +0800, Jiqian Chen wrote:
>> Refactor REGISTER_VPCI_INIT to contain more capability specific
>> information, this will benefit further follow-on changes to hide
>> capability when initialization fails.
>>
>> What's more, change the definition of init_header() since it is
>> not a capability and it is needed for all devices' PCI config space.
>>
>> After refactor, the "priority" of initializing capabilities isn't
>> needed anymore, so delete its related codes.
>>
>> Note:
>> Call vpci_make_msix_hole() in the end of init_msix() since the change
>> of sequence of init_header() and init_msix().
>>
>> The cleanup hook is also added in this change, even if it's still
>> unused. Further changes will make use of it.
>>
>> Signed-off-by: Jiqian Chen <Jiqian.Chen@amd.com>
>> ---
>> cc: "Roger Pau Monné" <roger.pau@citrix.com>
>> cc: Andrew Cooper <andrew.cooper3@citrix.com>
>> cc: Anthony PERARD <anthony.perard@vates.tech>
>> cc: Michal Orzel <michal.orzel@amd.com>
>> cc: Jan Beulich <jbeulich@suse.com>
>> cc: Julien Grall <julien@xen.org>
>> cc: Stefano Stabellini <sstabellini@kernel.org>
>> ---
>> v7->v8 changes:
>> * Recover vpci_make_msix_hole() call in modify_decoding(), which was  deleted by wrong.
>> * Add some comment to describe why need to add vpci_make_msix_hole() in init_msix().
>>
>> v6->v7 changes:
>> * Change the pointer parameter of cleanup hook of vpci_capability_t to be const.
>>   If change parameter of init hook to be const will affect init_msix, and it assigns pdev
>>   to struct vpci_msix, so keep no const to expanding the impact.
>> * Delete the vpci_make_msix_hole() call in modify_decoding().
>> * Change __start_vpci_array from vpci_capability_t* array to vpci_capability_t array.
>> * Change the name "finit##_t" to be "name##_entry" and add a "name" parameter to macro
>>   REGISTER_VPCI_CAPABILITY.
>>
>> v5->v6 changes:
>> * Rename REGISTER_PCI_CAPABILITY to REGISTER_VPCI_CAPABILITY.
>> * Move vpci_capability_t entry from ".data.vpci" to ".data.rel.ro.vpci" and
>>   move the instances of VPCI_ARRAY in the linker scripts before *(.data.rel.ro).
>> * Change _start/end_vpci_array[] to be const pointer array.
>>
>> v4->v5 changes:
>> * Rename REGISTER_VPCI_CAP to REGISTER_PCI_CAPABILITY, rename REGISTER_VPCI_LEGACY_CAP to
>>   REGISTER_VPCI_CAP, rename REGISTER_VPCI_EXTENDED_CAP to REGISTER_VPCI_EXTCAP.
>> * Change cleanup hook of vpci_capability_t from void to int.
>>
>> v3->v4 changes
>> * Delete the useless trailing dot of section ".data.vpci".
>> * Add description about priority since this patch removes the initializing priority of
>>   capabilities and priority is not needed anymore.
>> * Change the hook name from fini to cleanup.
>> * Change the name x and y to be finit and fclean.
>> * Remove the unnecessary check "!capability->init"
>>
>> v2->v3 changes:
>> * This is separated from patch "vpci: Hide capability when it fails to initialize" of v2.
>> * Delete __maybe_unused attribute of "out" in function vpci_assign_devic().
>> * Rename REGISTER_VPCI_EXTEND_CAP to REGISTER_VPCI_EXTENDED_CAP.
>>
>> v1->v2 changes:
>> * Removed the "priorities" of initializing capabilities since it isn't used anymore.
>> * Added new function vpci_capability_mask() and vpci_ext_capability_mask() to remove
>>   failed capability from list.
>> * Called vpci_make_msix_hole() in the end of init_msix().
>>
>> Best regards,
>> Jiqian Chen.
>> ---
>>  xen/arch/arm/xen.lds.S    |  3 +--
>>  xen/arch/ppc/xen.lds.S    |  3 +--
>>  xen/arch/riscv/xen.lds.S  |  3 +--
>>  xen/arch/x86/xen.lds.S    |  2 +-
>>  xen/drivers/vpci/header.c |  3 +--
>>  xen/drivers/vpci/msi.c    |  2 +-
>>  xen/drivers/vpci/msix.c   | 13 ++++++++++--
>>  xen/drivers/vpci/rebar.c  |  2 +-
>>  xen/drivers/vpci/vpci.c   | 44 ++++++++++++++++++++++++++++++---------
>>  xen/include/xen/vpci.h    | 29 +++++++++++++++++++-------
>>  xen/include/xen/xen.lds.h |  2 +-
>>  11 files changed, 74 insertions(+), 32 deletions(-)
>>
>> diff --git a/xen/arch/arm/xen.lds.S b/xen/arch/arm/xen.lds.S
>> index 5bfbe1e92c1e..9f30c3a13ed1 100644
>> --- a/xen/arch/arm/xen.lds.S
>> +++ b/xen/arch/arm/xen.lds.S
>> @@ -57,6 +57,7 @@ SECTIONS
>>  
>>         *(.rodata)
>>         *(.rodata.*)
>> +       VPCI_ARRAY
>>         *(.data.rel.ro)
>>         *(.data.rel.ro.*)
>>  
>> @@ -64,8 +65,6 @@ SECTIONS
>>         __proc_info_start = .;
>>         *(.proc.info)
>>         __proc_info_end = .;
>> -
>> -       VPCI_ARRAY
>>    } :text
>>  
>>  #if defined(BUILD_ID)
>> diff --git a/xen/arch/ppc/xen.lds.S b/xen/arch/ppc/xen.lds.S
>> index 1366e2819eed..1de0b77fc6b9 100644
>> --- a/xen/arch/ppc/xen.lds.S
>> +++ b/xen/arch/ppc/xen.lds.S
>> @@ -51,11 +51,10 @@ SECTIONS
>>  
>>          *(.rodata)
>>          *(.rodata.*)
>> +        VPCI_ARRAY
>>          *(.data.rel.ro)
>>          *(.data.rel.ro.*)
>>  
>> -        VPCI_ARRAY
>> -
>>          . = ALIGN(POINTER_ALIGN);
>>      } :text
>>  
>> diff --git a/xen/arch/riscv/xen.lds.S b/xen/arch/riscv/xen.lds.S
>> index 8c3c06de01f6..edcadff90bfe 100644
>> --- a/xen/arch/riscv/xen.lds.S
>> +++ b/xen/arch/riscv/xen.lds.S
>> @@ -46,11 +46,10 @@ SECTIONS
>>  
>>          *(.rodata)
>>          *(.rodata.*)
>> +        VPCI_ARRAY
>>          *(.data.rel.ro)
>>          *(.data.rel.ro.*)
>>  
>> -        VPCI_ARRAY
>> -
>>          . = ALIGN(POINTER_ALIGN);
>>      } :text
>>  
>> diff --git a/xen/arch/x86/xen.lds.S b/xen/arch/x86/xen.lds.S
>> index 636c7768aa3c..8e9cac75b09e 100644
>> --- a/xen/arch/x86/xen.lds.S
>> +++ b/xen/arch/x86/xen.lds.S
>> @@ -135,6 +135,7 @@ SECTIONS
>>  
>>         *(.rodata)
>>         *(.rodata.*)
>> +       VPCI_ARRAY
>>         *(.data.rel.ro)
>>         *(.data.rel.ro.*)
>>  
>> @@ -148,7 +149,6 @@ SECTIONS
>>         *(.note.gnu.build-id)
>>         __note_gnu_build_id_end = .;
>>  #endif
>> -       VPCI_ARRAY
>>    } PHDR(text)
>>  
>>  #if defined(CONFIG_PVH_GUEST) && !defined(EFI)
>> diff --git a/xen/drivers/vpci/header.c b/xen/drivers/vpci/header.c
>> index f537f3f25d2a..469f4977441a 100644
>> --- a/xen/drivers/vpci/header.c
>> +++ b/xen/drivers/vpci/header.c
>> @@ -858,7 +858,7 @@ static int vpci_init_ext_capability_list(const struct pci_dev *pdev)
>>      return 0;
>>  }
>>  
>> -static int cf_check init_header(struct pci_dev *pdev)
>> +int vpci_init_header(struct pci_dev *pdev)
>>  {
>>      uint16_t cmd;
>>      uint64_t addr, size;
>> @@ -1054,7 +1054,6 @@ static int cf_check init_header(struct pci_dev *pdev)
>>      pci_conf_write16(pdev->sbdf, PCI_COMMAND, cmd);
>>      return rc;
>>  }
>> -REGISTER_VPCI_INIT(init_header, VPCI_PRIORITY_MIDDLE);
>>  
>>  /*
>>   * Local variables:
>> diff --git a/xen/drivers/vpci/msi.c b/xen/drivers/vpci/msi.c
>> index 66e5a8a116be..c3eba4e14870 100644
>> --- a/xen/drivers/vpci/msi.c
>> +++ b/xen/drivers/vpci/msi.c
>> @@ -270,7 +270,7 @@ static int cf_check init_msi(struct pci_dev *pdev)
>>  
>>      return 0;
>>  }
>> -REGISTER_VPCI_INIT(init_msi, VPCI_PRIORITY_LOW);
>> +REGISTER_VPCI_CAP(MSI, init_msi, NULL);
>>  
>>  void vpci_dump_msi(void)
>>  {
>> diff --git a/xen/drivers/vpci/msix.c b/xen/drivers/vpci/msix.c
>> index 74211301ba10..eb3e7dcd1068 100644
>> --- a/xen/drivers/vpci/msix.c
>> +++ b/xen/drivers/vpci/msix.c
>> @@ -703,9 +703,18 @@ static int cf_check init_msix(struct pci_dev *pdev)
>>      pdev->vpci->msix = msix;
>>      list_add(&msix->next, &d->arch.hvm.msix_tables);
>>  
>> -    return 0;
>> +    /*
>> +     * vPCI header initialization will have mapped the whole BAR into the
>> +     * p2m, as MSI-X capability was not yet initialized.  Crave a hole for
>> +     * the MSI-X table here, so that Xen can trap accesses.
>> +     */
>> +    spin_lock(&pdev->vpci->lock);
>> +    rc = vpci_make_msix_hole(pdev);
>> +    spin_unlock(&pdev->vpci->lock);
> 
> I should have asked in the last version, but why do you take the vPCI
> lock here?
> 
> The path that ASSERTs the lock is held should never be taken when
> called from init_msix().  Is there some path I'm missing in
> vpci_make_msix_hole() that requires the vCPI lock to be held?
> 
> The rest LGTM.
Sorry to forget to delete this.
Feel free to change when submit.
Or I will change by sending a new version.

> 
> Thanks, Roger.

-- 
Best regards,
Jiqian Chen.

On Fri, Jul 25, 2025 at 03:15:13AM +0000, Chen, Jiqian wrote:
> On 2025/7/24 22:28, Roger Pau Monné wrote:
> > On Thu, Jul 24, 2025 at 01:50:00PM +0800, Jiqian Chen wrote:
> >> diff --git a/xen/drivers/vpci/msix.c b/xen/drivers/vpci/msix.c
> >> index 74211301ba10..eb3e7dcd1068 100644
> >> --- a/xen/drivers/vpci/msix.c
> >> +++ b/xen/drivers/vpci/msix.c
> >> @@ -703,9 +703,18 @@ static int cf_check init_msix(struct pci_dev *pdev)
> >>      pdev->vpci->msix = msix;
> >>      list_add(&msix->next, &d->arch.hvm.msix_tables);
> >>  
> >> -    return 0;
> >> +    /*
> >> +     * vPCI header initialization will have mapped the whole BAR into the
> >> +     * p2m, as MSI-X capability was not yet initialized.  Crave a hole for
> >> +     * the MSI-X table here, so that Xen can trap accesses.
> >> +     */
> >> +    spin_lock(&pdev->vpci->lock);
> >> +    rc = vpci_make_msix_hole(pdev);
> >> +    spin_unlock(&pdev->vpci->lock);
> > 
> > I should have asked in the last version, but why do you take the vPCI
> > lock here?
> > 
> > The path that ASSERTs the lock is held should never be taken when
> > called from init_msix().  Is there some path I'm missing in
> > vpci_make_msix_hole() that requires the vCPI lock to be held?
> > 
> > The rest LGTM.
> Sorry to forget to delete this.
> Feel free to change when submit.
> Or I will change by sending a new version.

Can you ensure it also works without the locking?  I think so, but I
haven't tested myself.

Thanks, Roger.

On 2025/7/25 16:08, Roger Pau Monné wrote:
> On Fri, Jul 25, 2025 at 03:15:13AM +0000, Chen, Jiqian wrote:
>> On 2025/7/24 22:28, Roger Pau Monné wrote:
>>> On Thu, Jul 24, 2025 at 01:50:00PM +0800, Jiqian Chen wrote:
>>>> diff --git a/xen/drivers/vpci/msix.c b/xen/drivers/vpci/msix.c
>>>> index 74211301ba10..eb3e7dcd1068 100644
>>>> --- a/xen/drivers/vpci/msix.c
>>>> +++ b/xen/drivers/vpci/msix.c
>>>> @@ -703,9 +703,18 @@ static int cf_check init_msix(struct pci_dev *pdev)
>>>>      pdev->vpci->msix = msix;
>>>>      list_add(&msix->next, &d->arch.hvm.msix_tables);
>>>>  
>>>> -    return 0;
>>>> +    /*
>>>> +     * vPCI header initialization will have mapped the whole BAR into the
>>>> +     * p2m, as MSI-X capability was not yet initialized.  Crave a hole for
>>>> +     * the MSI-X table here, so that Xen can trap accesses.
>>>> +     */
>>>> +    spin_lock(&pdev->vpci->lock);
>>>> +    rc = vpci_make_msix_hole(pdev);
>>>> +    spin_unlock(&pdev->vpci->lock);
>>>
>>> I should have asked in the last version, but why do you take the vPCI
>>> lock here?
>>>
>>> The path that ASSERTs the lock is held should never be taken when
>>> called from init_msix().  Is there some path I'm missing in
>>> vpci_make_msix_hole() that requires the vCPI lock to be held?
>>>
>>> The rest LGTM.
>> Sorry to forget to delete this.
>> Feel free to change when submit.
>> Or I will change by sending a new version.
> 
> Can you ensure it also works without the locking?  I think so, but I
> haven't tested myself.
Yes, before I replied to you last email.
I have tested locally. MSI-X and other things work fine.

> 
> Thanks, Roger.

-- 
Best regards,
Jiqian Chen.